THE BLACKOUT

Published: August 16, 2003 8:00PM

WASHINGTON (AP) A failure to contain problems with three transmission lines in northern Ohio just south of Cleveland was the likely trigger of the nations biggest power blackout, a leading investigator said Saturday.

Experts are working to understand why the local line disruptions, some of which occurred an hour before the blackout reached its peak, were not isolated, allowing a cascade of power system shutdowns stretching from Michigan to New York City and into Canada.

We are fairly certain at this time that the disturbance started in Ohio, Michehl Gent, head of the North American Electric Reliability Council, said in a statement. We are now trying to determine why the situation was not brought under control after three transmission lines went out of service.

Gent said the transmission system was designed to isolate such problems and suggested that human error might have been involved in not containing the situation.

The system has been designed and rules have been created to prevent this escalation and cascading. It should have stopped, said Gent in a telephone conference call.

Later, in a statement suggesting human failings for the events last Thursday, Gent said in the future system operators ... will be extremely vigilant when local transmission problems arise.

Energy Secretary Spencer Abraham, who is co-chair of a U.S.-Canadian task force that will look into the cause of the blackout, said its still too early to pinpoint a cause.

Were not going to prejudge where the problem is, Abraham told reporters in Albany, N.Y., on Saturday where he met with the governors of New York and New Jersey.